The effect of time and temperature on shelf life of essential oil composition of L.

has been used to treat gastrointestinal disorders, inflammation, diabetes and rheumatism. This plant has beneficial therapeutic properties. In this research the changes in the composition of essential oils from the aerial parts of were determined at different temperatures and times. The essential oil of air-dried samples was obtained by hydro distillation and analyzed by gas chromatography/mass spectrometry (GC/MS). Changes in essential oils compositions were detected during storage for 3 months in refrigerator, freezer, and at room temperature. The results indicated that at room temperature, the proportions of the compounds with lower boiling temperatures such as Cis-Verbenol (2.11-1.78%) and Germacrene D (1.56-0.94%) were decreased significantly. Furthermore, the essential oil composition showed the least alterations and L. kept its primary quality when stored at low temperatures, particularly in refrigerator and freezer (Except: α-Pinene, β-Pinene and Limonene).